1. Field of the Invention
This invention relates generally to clamps and to a jig for use therewith.
2. Description of the Prior Art
There are many examples of clamps in the prior art but few, if any, combine with a large holding power the highly desirable features of being both self-centering and capable of accepting a wide range of workpiece thicknesses without adjusting the position of one jaw relative to the other. Over-centering or "knuckle" type clamps are typical examples of the prior art.
However, when a high degree of accuracy is desirable, where rapid opening and closing of the clamp is needed and where great holding power is required it has been found that prior art clamps have not been entirely satisfactory.
One example of where the prior art clamps have not been entirely successful is in a jig for sharpening ice-skate blades. It is well known that the blades of figure, hockey and speed skates each have a different thickness and that a range of thicknesses are also available for each type of blade. In addition, figure blades are also tapered from toe to heel, are hollow ground on the bottom and may even be hollow ground on the sides to produce a sharp edge.
Normally, ice skate blades are clamped in a jig and brought into engagement with an abrasive member such as a rotating grinding stone that has been very accurately dressed. If the clamp is not self-centering it will be impossible to apply the entire length of the blade to the same spot on the stone, particularly if the blade thickness varies, as described above. If the clamp cannot accept a range of thickness and still be self-centering it will be virtually worthless for use with all the different thickness ice skate blades. That is, the clamp jaws or the entire jig would have to be adjusted to suit each blade thickness and this would be intolerably time consuming.